Prevention of enzyme deactivation by chlorine

ABSTRACT

Enzyme deactivation during fabric laundering in water is prevented by using the enzyme in combination with a chlorine scavenger which is capable of reacting with residual chlorine in the water.

United States Patent [191 Tivin et a1.

l PREVENTION OF ENZYME DEACTIVATION BY CHLORINE [75] Inventors: FredTivin, Springfield Twp.; Eugene Zeffren, Wyoming, both of Ohio [73]Assignee: The Procter & Gamble Company,

[52] U.S. Cl 195/68, 195/63, 252/89,

252/D1G. 12 51 Int.Cl ..C07g 7/02 [58] Field of Search 195/63, 68, 66;

[451 Aug. 28, 1973 [56] References Cited UNITED STATES PATENTS 3,189,5186/1965 Glasgow 210/62 X' Primary Examiner-David M. Naff Attorney-JuliusP. Filcik and Richard c. Wine [57] ABSTRACT v Enzyme deactiyation duringfabric laundering in water is prevented by using the enzyme incombination with -21 chlorine scavenger which is capable of reactingwith residual chlorine in the water.

2 Claims, No Drawings PREVENTION OF ENZYME DEACTIVATION BY CHLORINEFIELD OF INVENTION BACKGROUND OF INVENTION AND PROBLEMS CONNECTEDTHEREWlTl-I Enzymes are organic catalytically-active protein materialswhich in very low amounts speed up certain chemical reactions. One oftheir known functions is to I break down various types of organic matter(carbohydrates, fats, proteins) into simpler particles, e.g., enzymesthat are found in the human digestive system break down food materialsinto smaller, more assimilable forms. When used in detergentcompositions, the enzymes function to break down soils and stains intosimpler forms so they can be more easily removed by other detergentingredients and the washing action.

Enzymes are complex molecules and are subject to attack and deactivationby many different conditions which prevail depending upon the differentapplications of the enzymes. For instance, incompatibility of enzymesand detergent ingredients such as chlorine bleaching agents isrecognized; for example, an article published in Detergent Age,September, 1968, by Dr. Howard E. Worne, titled The Role of Enzymes inDetergent Compositions states:

Bleaching agents such as perborates, peroxides, or

compounds containing active chlorine, strongly inhibit the reaction ofproteolytic enzymes, and as such, they must be eliminated from allproposed formulations. v

For this reason, care is exercised in formulating detergent compositionsin which an enzyme component is contemplated. US. Pat. No. 3,451,935discusses some highly useful ways of overcoming the problems Iencountered. While this latter discovery has advanced the art materiallyand has provided, for the first time, large scale production ofgenuinely effective granular enzyme-containing detergent compositions,it has more recently been discovered that additional problems areencountered in actual usage situations.

Further evaluations have shown that the full potential benefit ofenzymatic activity in detergent compositions has not always been enjoyedin practical ordinary household situations. The reason for this has goneunrecognized until the present invention.

It has now been discovered that enzyme activity can besubstantiallydecreased by deactivation of the enzyme component by even small amountsof residual chlorine present in domestic water supply sources. It isthis heretofore unappreciated problem that is solved by the presentinvention.

There are two basic ways of treting waste as part of pollution controlin the United States. They are referred to generally as primary andsecondary treatments. In a primary treatment, solids are allowed tosettle and are removed from the water. The secondary treatment methoduses biological processes. A common step in both of these treatmentmethods involves the addition to the water of varying amounts of freeavailable chlorineas gaseous chlorine or hypochlorites.

A major purpose for the chlorine addition is to kill disease producingbacteria, although it also helps to reduce odors. I

While a portion of the added chlorine escapes from the water during thetreatment and handling steps, it has been found that a portion ofresidual chlorine remains in municipal water-supplies. This residualchlorine is sufficient to substantially deactivate an enzyme when it isadded to such water.

A major object of this invention is to provide significantly improvedbenefits in the area of cleaning and laundry performance resultsobtained with enzymecontaining detergent compositions. While detergentcompositions and washing processes represent preferred embodiments ofthis invention, it, in fact, finds wider application. The invention canbe applied broadly to all enzyme usages in water which contains residualchlorine.

SUMMARY OF THE INVENTION AND PREFERRED EMBODIMENTS It has now beendiscovered that the deactivation of an enzyme by residual chlorine inwater can be prevented by using the enzyme in combinationwith ahydroxyamine chlorine scavenger which is capable of reacting with. theresidual chlorine to form chloramines.

The hydroxyamine chlorine scavenger of the present invention has thefollowing formula:

wherein each of R", R, and R is selected from the group consisting ofhydrogen, and alkyl or hydroxyalkyl groups having from 1 to 6 carbonatoms. The alkyl groups can be straight'chainor branch chain and thehydroxy can be present on any of the carbon atoms.

The following compounds are illustrative of those which can be used inpracticing the present invention:

methylamine,

ethylamine,

l -propylamine,

l-butylamine,

l-pentylamine,

3-amino-l-propanol,

l-amino-Z-propanol, l-amino-2-butanol,.

l.-amino-3-butanol,

l -a.mino-4-butanol,

I-amino-Z-pentanol,

1-amino-3-pentanol,

l-amino-4-hydroxypentane,

l-amino-S -hydroxypentane,

2-amino-2-methyll -propanol,

2-amino-2-methyll -butanol,

2-amino-2-methyll -penta.nol,

2-amino-2-methyll -hexanol,

2-amino-2-methyll ,3-butanediol,

Z-amino-Z-methyl-l ,4.-butanediol,

2-amino-2-methyl-l ,3-pentanediol,

2-arnino-2-methyl-l ,4-pentanediol,

2-amino-2-methyl-l ,5 -pentanediol,

2-amino-2-methyl-l ,3'-hexanediol,

2-arnino-2-methyl-l ,4-hexanediol,

2-amino-2-methyl-1,5-hexanediol,

2-amino-2-methyl-l ,6-hexanediol.

2-aminol ,3-propanediol,

2-amino-2-methyl-l ,3propanediol,

2-amino-2-hydroxymethyl- 1 -butanol,

After neutralizing the catalyst and stripping off unreactedformaldehyde, the nitroalcohol is vnext reduced over Raney nickel to thecorresponding amine. Carbon dioxide is added to the hydrogen stream inthe reduction process to neutralize the amine as it is formed. Thisvprevents side reactions which would'otherwise occur between the amineand the nitroalcohol.

Aminohydroxy compounds which are representative of the type which areuseful in the present invention are further described below:

mcth yl-lmethyl-1,21- ethyl-1,3, tris(hy lrx ymethyl Physical properties2-amino-1-butanol pro panol propanediol propanediol amlnomethang Formulaz N NH: NH: NH;

Molecular weight 89.1 105.14 119. 17 121. 14

Boiling point, C 178 165 mm 151-152 mm 152-153 219-220 Melting point, C.t -2 30-31 109-111 37. 5-38. 5 171-172 Specific gravity at /20 C 0. 944

pH 010.1 M aqueous solution at 20 C... 11.1 11.3 10. 8 10.8 10. 4

Solubility in water at 20 0., g./10O m1. 250 80 1 Completely miscible.

2-amino-2-hydroxymethyl-1,S-hexanediol,

2-amino-2-hydroxyrnethyl-1,-hexanediol,

1 -amino-1 -ethanol,

Z-amino- 1 -propanol,

Z-amino- 1 -butanol,

2-amino-1-pentanol,

Z-amino- 1 -hexanol 2-amino-1,4-butanediol,

2-amino-l ,3-butanediol,

2-amino-1,3-pentanediol,

2-amino-1 ,4-pentanediol,

Z-amino-l ,S-pentanediol,

2-amino-l ,3-hexanediol,

Z-amino-l ,4-hexanediol,

2-amino-1,5-hexanediol,

2-amino-l ,6-hexanediol.

The hydroxyamines of the present invention can be prepared by manydifferent syntheses. One satisfactory general method involves reacting anitroparraffin with formaldehyde in the presence of a caustic catalystto yield a nitroalcohol. This reaction is a condensation of the aldoltype in which one, two or three of the hydrogen atoms attached to thecarbon atom holding the nitro group may add to the oxygen of theformaldehyde with the formation of hydroxy methyl-substitutednitroparaffins.

THe following equations illustrate the general application of this typeof a reaction:

Further suitable. synthesis procedures are found in the followingpatents and technical literature references: U.S. Pats, No. 2,755,304granted July 17, 1956, and No. 2,946,793 granted July 26, 1960; JapanesePat. No. 1,235, dated Feb. 24, 1955 Preparation of amino alcohols foundin comp. rend. congr. sci. savantes Paris etdepts, Sect. sci. 1955,89-93; Great Britain Pats, No. 764,183 published Dec. 19, 1956; No.758,941 published Oct. 10, 1956; No. 760,215 published Oct. 31, 1956;No. 839,317 published June 29, 1960; Preparation of B-amino alcoholsdescribed by J. H. Hunt and D. McHale (Allen & Hanburys, Ltd., Herts,Engl.) J. Chem. Soc. 1957, 2073-7; West Germany Pat. No. 1,096,917published Jan. 12, 1961.

The invention can be practiced according to several embodiments.Preferably, an enzyme composition is prepared embodying the invention.Such a composition comprises a mixture of an enzyme (either a pureenzyme or an ordinary enzyme preparation consisting of a powder mixtureof an activeenzyme ingredient and inert salts which are ordinarily foundin commercial enzyme preparations such as, for example, sodium andcalcium sulfates) and a hdyroxyamine chlorine scavenger of the typespecified above. The amount of each ingredient depends on the use of thecomposition. For maximum benefits, there should be an amount ofhydroxyamine chlorine scavenger sufficient to overcome the residualchlorine. For any given purpose, the

N itroparaifin Formaldehyde Intermediate aldol product CH=NO1 plus SCHzON02 CHzOHC CHzOH CHzOH (N itromcthane) (tris(Hydroxymethyl)nitromethane)(l-nitropropane) 1CH2O NO; NO; OHJCHCHS 011380112011 (.Zqutropropane)(2-nitro-2-ethyl-1,3-propanediol).

(2-nitro-2-methyl-1-propan01).

Another important aspect of the present invention is the totallyunexpected discovery that when the amount of hydroxyamine chlorinescavenger in a detergent product exceeds the amount of residual chlorinein wash water .(on a molar basis), I the enzyme stainremoval cleaningperformance is significantly greater than the cleaning achieved by ahydroxyamine-free enzyme product in chlorine-free water. This uniqueperformance advantage is not completely understood. It is postulated,however, to be due to the hydroxyfunctionality of the hydroxy-amineparticipating in the enzyme catalyzed stain-removal reaction.

As an alternative embodiment to preparing a mixture of an enzyme and ahydroxyamine chlorine scavenger of this invention, the benefits of thisinvention also can be obtained by following a procedure in which aneffective amount of a hydroxyamine chlorine scavenger is added to watercontaining residual chlorine and in another step adding the enzymecomposition, e.g., as an enzyme containing detergent composition.

The present invention finds application with all types of enzymes whichare inactivated by chlorine in water including proteases, lipases,amylases, carbohydrases, esterases, and many others. A description ofthe types of enzymes which can be protected by practice of the presentinvention appears in U.S. Pat; No. 3,451,935, beginning at Column 6,line 1, and extending to C01- umn 9, line 28. This disclosure isincorporated herein by reference. The preferred enzymes for use inpractic ing this invention, especially for the detergent compositionembodiments, are proteases, lipases and amylases (alpha and beta).

This invention finds special application and provides excellentunexpected improvements in the area of desure is hereby incorporatedherein by reference. The

preferred detergents are the anionic class including specifically soapand non-soap anionic detergents such as sodium alkyl benzene sulfonates,the alkyl group being linear or branch and having 10 to 18 carbon atoms,preferably 12 to 16; sodium and potassium alkyl I sulfates, the alkylgroup having 10 to 18 carbon atoms,

e.g., sodium coconut and tallow alkyl sulfate, sodium salt of acondensation reaction product of tallow or coconut alcohol with 1 to 20ethylene oxide groups, preferably 2 to-l2 ethylene oxide groups, suchail-sodium tallow alkylethoxylate averaging three moles of ethyltergencyand especially household laundry compositions.

The invention can be practiced by preparing compositions containing onlyan enzyme preparation and an effective amount of a hydroxyamine asdescribed above. Soiled garments which comprise an ordinary householdwashing load can be treated, e.g., soaked and/or washedwith such acomposition.

A preferred practice is touse such a binary mixture in combination withan organic synthetic detergent to provide a more complete cleaning andlaundry compoene oxide per mole of tallow alcohol; sodium olefinsulfonates in which the olefin has 10 to 18 carbon atoms, e.g., sodiumdodecene sulfonates, sodium hexadecene sulfonates, and mixtures of theanionic detergents. 7

An unbuilt detergent composition of the present invention comprises from1 to 99 percent of an organic synthetic detergent, from 1 to 99 percentof an enzyme, and an effective amount of a hydroxyami'ne chlorinescavenger of the type described above. An effective amount can rangefrom 0.001 to 5 percent by weight of the composition, preferably from0.005 to 2 percent by weight.

For heavy-duty laundering applications, a preferred embodiment of thisinvention is a detergent composition which comprises from 0.001 to 10percent of an enzyme, from 0.001 to 5 percent of an hydroxyaminechlorine scavenger of the type described above and from about 1 to99.998 percent of a mixture of an organic synthetic detergent and adetergency builder salt, the ratio by weight of said detergent to saidbuilder being in the range of 10:1 to 1:20, and preferably from 5:1 to1:10. Such a composition provides a pH in aqueous solution in therangeof 7 to 12; optimum results are obtained in a pH range of 8 1 1.5.

The detergency builder component can be an inorganic or organic alkalinebuilder of the type described below.

Examples of suitable water-soluble,' inorganic alkaline detergencybuilder salts are alkali metal carbonates, borates, phosphates,polyphosphates, bicarbonates, silicates and sulfates. Specific examplesof suchane-l-hydroxy-l,l-diphosphonic acid, sodium, potassium andlithium salts of methylene diphosphonic acid, sodium, potassium andlithium salts of ethylene diphosphonic acid, and-sodium, potassium andlithium salts of ethane-l,l,2-triph0sphonic acid. Other examples includethe alkali metal salts of ethane-2-carboxy-l,ldiphosphonic acid,hydroxymethanediphosphonic acid, carbonyldi-phosphonic acid,ethane-l-hydroxy-1,1,2- triphosphonic acid, ethane-2-hydroxy-1 ,1 ,2-triphosphonic acid, propane-l ,1 ,3,3-tetraphosphonic acid,propane-1,1,2,3-tetraphosphonic acid, and propane-l,2,2,3-tetraphosphonic acid; water-soluble salts of polycarboxylatepolymers and copolymers as described in US. Pat. No. 3,308,067. Specificexamples are polymers of itaconic acid, aconitic acid, maleic acid,mesaconic acid, fumaric acid, methylene malonic acid, and citraconicacid and copolymers with themselves and other compatible monomers suchas ethylene.

Mixtures of organic and/or inorganic builders described above can beused and are generally desirable. One such mixture of builders isdisclosed in US. Pat. No. 3,392,121, e.g., ternary mixtures of sodiumtripolyphosphate, sodium nitrilotriacetate and trisodium ethane- 1-hydroxy-l 1 -diphosphonate.

In these heavy-duty formulations, the detergent can be either a singleactive detergent or a mixture thereof. Similarly, the builder can be asingle builder or a mixture of two or more builders.

The present invention can be effectively used in water having a pH inthe range of 4 to 12 depending upon the specific ingredients employed.Builderless systems are effective in slightly acid to neutral soakingand washing systems. The built compositions, however, provide optimumcleaning performance results in an alkali pH range, i.e., 7 to 12 andpreferably 8 to 11.5.

The following examples serve to demonstrate the present invention. Theyillustrate the unexpected performance benefits made possible by using ahydroxyamine chlorine scavenger in combination with an enzymecomposition whereby the problem of enzyme deactivation in chlorinatedwash water is substantially eliminated.

In the following examples, the enzyme preparation consisted of a mixtureof 3.42 percent by weight Bacillus subtilis Carlsburg protease (1.5Anson units), 2.28% by weight BPN protease (1.5 Anson units). The enzymepreparation also had 7500 a-amylase activity units per gram of saidpreparation. In the following examples, the enzyme-containing benchmarkproduct was prepared by adding 3.6 parts of the foregoing enzymepreparation to 96.4 parts (all by weight) of the spray-dried benchmarkproduct.

EXAMPLE 1 Cotton muslin swatches (each inches square) stained withlicorice, gravy, and spinach were washed in 1.5 gallon automaticminiature washers (AMW) at three temperatures. Previously unwashedstained swatches were used for each temperature. Four washers wereemployed (AMW Nos. 1, 2, 3, and 4).

The stained muslin swatches were prepared by passing strips of muslinthrough a padding batch containing a staining solution, passing themuslin through a tworoll wringer and then drying the stained muslinstrips. In order to effect deeper stains, the muslin strips were passedthrough the staining bath a second time followed by drying over night at120 F. The strip of muslin was then cut into swatches approximately 5%inches square in size.

The wash load in each AMW consisted of three swatches of each differentstain plus two 12 inches square unstained (total items), whiteterrycloths. The terrycloths provide bulk for the wash load and promotemore precise stain removal data by providing more even agitation. Theeven agitation is desired because it minimizes the tendency for theswatches to intertwine, twist, or curl.

A series of washes was conducted demonstrating the invention using F.water, F. water and F. water. These are nominal temperatures. The actualtemperatures were slightly lower because the water cooled slightlyduring the procedures.

The benchmark product used in these demonstrations was a spray driedbuilt detergent composition having the following ingredients by weight:

Weight Sodium linear alkyl benzene sulfonate (alkyl group having anaverage 13.0 carbons) 12.6 Sodium tripolyphomhate 41.5 Sodiumnitrilotriacetate 9.6 Sodium silicate (1.6 R) 7.0 Water 10.0 Sodiumsulfate 14.0 E epre nasdescn'bed above .2 Ciifixyme yloellulose .2Miscellaneous (including brighteners, perfume) Balance to 100%Additional conditions in each washer are given in Automatic miniaturewasher Table 1 indicates that the conditions which prevailed in AMW No.1 were no enzyme, no chlorine, and no chlorine scavenger. Essentiallythis provided results using just the benchmark detergent product shownabove.

The conditions in AMW No. 2 differed from AMW No. 1 in the addition tothe benchmark detergent product of 0.2 percent of an enzyme ingredient.

The conditions in AMW No. 3 differed from AMW No. 2 in the presence of1.5 ppm concentration of chlorine in the wash water.

The conditions in AMW No. 4 differed from AMW No. 3 in the addition tothe benchmark detergent product of 0.5 parts of a hydroxyamine chlorinescavenger which was tris(hydroxymethyl) amino methane (TRIS).

These varied conditions provided an opportunity to demonstrate thepresent invention with meaningful comparisons.

The washing procedure consisted of the following steps:

Step 1. The automatic miniature washers (AMW) were filled to their 1.5gallon capacities with water of the desired washing temperature.

Step 2. The water hardness was adjusted to 7 gr./ga1. by adding 5.5 m1.of a solution which is 7,570 gr./cc. hardness (3 pts. Ca/l pt. Mg. bothexpressed as CaCO,). Hardness contribution from the load was neglected.

Step 3. The chlorine concentration of each washer was adjusted. Toprovide for a dmonstration for comparative purposes of 0.0 ppm C1,, 1ml. of a 0.1N Na,S,O solution was added to the washer. To achieve 1.5ppm Cl 3.9 ml. ofa chlorine solution (made from adding 3 parts water to1 part of an aqueous solution containing 0.4% G1,.) was added to thewasher.

Step 4. The product being demonstrated was added to the washer, and thewater was agitated for two minutes. The product in AMW No. 4 (see TableI above) was made by adding 0.5 parts of 99+ percent pure TRIS chlorinescavenger to 99.5 parts of the above identified benchmark product.

Step 5. After this two-minute agitation, the stain swatches were added.The load was washedfor minutes followed in order by a spin, a rinse, andanother spin to damp dry.

Step 6. Each load was tumbled to dryness in a steam dryer operating at160 F. maximum.

Step 7. Each swatch (except the spinach) was ironed. The spinachswatches were smoothed out by hand.

Step 8. Hunter Whiteness grades were obtained for each swatch for aHunter Color Difference Meter. This instrument is designed todistinguish color difierences and operates on the tristimuluscolorimeter principle wherein the 45 diffuse reflectance of an incidentlight obtained into a complex formula supplied by the manufacturer. Anevaluation of relative whiteness performance compared to a standarddetergent composition is thus obtained for the test formulations. Theseare later compared with other values obtained from other test samples.

A more comprehensive description of this instrument and its mode ofoperation appears in Color in Business, Science and Industry, by DeaneB. Judd, pages 260-262; published by John Wiley & Sons, New York (1952).

The results are shown in Table lLThe product used in AMW No. 1 withoutenzyme in 0.0 ppm. Cl, serves as the benchmark for measuring theeffectiveness of the present invention as illustrated in AMW No. 4. Theleast significant difference at a=0.05, (LSD is shown for each stain ineach treatment in Table 11.

The first column, (AMW No. 2-AMW No. 1), shows the degree of improvementin whiteness cleaning, in terms of Hunter Units, when an enzymeingredient is used with the benchmark product in 0.0 ppm C1 The secondcolumn, AMW No. 3AMW No. 1), illustrates the deterioration inperformance when the benchmark product with an enzyme ingredient is usedin chlorinated wash water. All A W values less than LSD (column 5)indicate no significant performance advantage for the E-base inchlorinated water. Each of g g 10 hydroxymethyl) aminomethane, referredto at times in this specification as TRIS. It is notable that, in eachcase, cleaning due to enzyme activityin chlorinated water wasnot onlyrestored but actually increased to levels greater than enzyme cleaningperformance in non-chlorinated water. These results indicate that thedetergent compositions of this invention are synergetic detergentcompositions providing an unexpectedly superior level of cleaning. Thesesynergetic results are obtained even with wash waters havingtemperatures ranging from cool water to hot water. This is evidencedwith the spinach, gravy, and licorice stains demonstrated in Table I].

The AW values are the difference between the first and second washersidentified in each column.

Chlorine Level Additives in Wash Water "AMW N0. lzUsed benchmark roduct0.0% Eben: 0.0% TRIS 0.0

ppm Cl, AMW No. 2:Used benc mark product+0.20% E-hane+0.0%

TRIS 0.0 pm Cl, AMW No. 31Uled benchmark product-+0.20% F.- base+0. TRIS1.5 ppm Cl, AMW No. 41U|ed benchmark product-+0.20% E-bale+0.5 TRIS 1.5ppm Cl,

EXAMPLES ll V The procedures described in Example 1 above were repeatedwith other illustrative aminohydroxy chlorine scavenger compounds at andF. washing temperatures. The aminohydroxy compounds were used at thesame level as Example 1 (i.e., 0.5 parts aminohydroxy scavenger added to99.5 parts benchmark product. The results are shown in Table 111. Here AW values represent the difference in Hunter Whiteness Units betweenvalues obtained with the benchmark product with an enzyme and achlorinescavenger and the benchmark product with an enzyme but without aprotective chlorine scavenger (both operating in 1.5 ppm Cl wash water).

The 2-amino-2-methyl-l,3-propanediol (AMPD) and the2-amino-2-ethyl-l,3-propanediol (AEPD) exhibit comparable chlorinescavenging effectiveness for all three stains at both temperatures,i.e., 75 F. and 125 F. The Z-amino-I-butanol and l-amino-Z- propanolexhibit maximum chlorine scavenging effectiveness at 125 F.

TABLE III Example AW .Example E l IV Example V l Ill Z-aminO- Z-aZ-amino- 1-amino 2-methyl- 2-ethyl- T=75 F. l,-3- 1,3-prw l-butanol2-propanol propanediol panediol Spinach 5.9 2.4 -0.2 -2.6 Gravy 6.0 4.7-0.8 1.2 Licorice 1.2 3.8 +0.3 0.5 T=l25 F. Spinach 10.4 14.9 3.7 4.1

Gravy l2.l 13.9 4.3 3.9 Licorice 1.9 4.0 -0.8 0.4

EXAMPLE VI Results similar to those achieved in Example I are obtainedwhen the following hydroxyamine chlorine scavengers are substituted inwhole or in part for the TRIS scavenger in Example I: methylamine,lpentylamine, 3-amino-2-propanol, 1-amino-4-hydroxypentane,

2-amino-2-methyll -butanol, 2-amino-l ,3- propanediol;2-amino-2-hydroxymethyl-l ,6- hexanediol, l-aminol -lethanol, Z-amino-l,4- hexanediol.

EXAMPLE VII A synergetic detergent composition of the present inventioncomprises:

Sodium dodecyl benzene sulfonate 20 (dodecyl being linear) Sodiumtripolyphosphate 50 Sodium silicate (L6 R) l Sodium sulfate 15 Water 4.4Alcalase proteolytic enzyme .3

Tris( hydroxymethyl )aminomethane chlorine scavenger This conposition iseffective in wash waters containing up to 10 ppm chlorine. When thiscomposition is used under washing conditions in which the molarconcentration of chlorine scavenger exceeds that of the residualchlorine an unexpectedly superior stain removal is achieved.

EXAMPLE VIII When the following hydroxyamine compounds are substitutedwholly or partially for the TRIS of Example VII, substantially similarresults are achieved: Z-amino- 2-methyl-l ,3-propanediol;2-amino-2-ethyl-l ,3- propanediol; 2-amino-l-butanol;l-amino-2-propanol.

Whereas the preceding examples illustrate the composition embodiments ofthe present invention, it is to be noted that the hydroxyamine chlorinescavengers can just as effectively be added in an effective amount tothe chlorine-containing wash water in a. separate step prior to awashing step.

In this manner, the residual chlorine is reacted with the hydroxyaminechlorine scavenger and is thus not available to attack and deactivate anenzyme ingredient which is added to the water such as anenzymecontaining laundry detergent composition.

EXAMPLE IX Wash wter containing 3.5 ppm residual chlorine and having atemperature of 120 F. is provided. A chlorine scavenger compound whichis tris(hydroxymethyl- )aminomethane is added to the wash water in anamount of 6 ppm. This amount corresponds to molar parity between thescavenger and the chlorine. Soiled and stained garments are added to thewash water and laundered therein using the benchmark compositiondescribed in Example I. Superior stain removing performance results areobtained as compared to this process in which the chlorine scavenger isomitted.

EXAMPLE X In Example IX, synergetic cleaning results are obtained whenthe amount of tris(hydroxymethyl) is increased to 12 ppm.

EXAMPLE XI A soaking detergent composition providing synergetic stainremoving properties comprises:

Sodium linear dodecyl benzene sulfonate 99% Alcalase protease enzyme .5%

Tris(hydroxymethyl)aminomethane 5% EXAMPLE XII In Example XI,substantially the same results are obwherein each of R R, and R, isselected from the group consisting of hydrogen and alkyl or hydroxyalkylgroups having from I to 6 carbon atoms in an amount sufficient toovercome residual chlorine in the water; and thereafter b. adding to thewater an enzyme. g

2. A method according to claim 1 in which the chlorine scavenger istris(hydroxymethyl)aminomethane.

i i =8 t

2. A method according to claim 1 in which the chlorine scavenger istris(hydroxymethyl)aminomethane.